Field of the Invention
This invention relates to an arrangement for fastening an exhaust manifold on to the cylinder head of an internal combustion engine.
An exhaust manifold of the generic type is disclosed in DE 196 35 870 A, and a typical earlier fastening of the exhaust manifold to the cylinder head can be seen from DE 38 28 723 A.
To accommodate thermal growth or expansion of the exhaust manifold and inhibit warping, the manifold's flanges which are used to attach it to a cylinder head permit sliding movement of the manifold along the sealing surface with the engine, along either a seal member of the actual surface of the cylinder head itself. For this purpose, holes in the inlet flanges of the manifold are made larger than the diameters of the fasteners, either bolts or studs and nuts, and are designed as slots. However, the fasteners have to be tightened with a defined torque to extremely small tolerances, e.g. 16 Nm.+-.1 Nm to both permit desired sliding movement and also adequate sealing. In an installation where several fasteners are installed in series for a given manifold, much time is expended to satisfy attach the manifold because the fasteners must be tightened in sequence and gradually using at least two torque settings for the installation tool. In addition to this difficulty, there is only a small degree of certainty of a proper reinstallation of a manifold after servicing in the workshop where such narrow tolerances likely cannot be achieved.